1. Field of the Invention
This invention relates generally to control assemblies and more particularly to automatic control and distribution systems for irrigation and fertilization.
2. Description of the Prior Art
A simple irrigation system that has been in use for centuries includes a network of irrigation ditches that are periodically or continuously flooded with water to bring needed moisture to the plants. This type of irrigation system, while inexpensive, is very wasteful of water resources.
A more modern irrigation system utilizes a pressurized water source, a water distribution network typically including a series of pipes and spray heads, and a control assembly coupling the pressurized water source to the water distribution network. The control assembly can be as simple as a manually operated valve, or as complex as an electronic device responsive to a number of environmental parameters and operative to deliver the optimal amount of moisture to the plants.
While inexpensive, a manually operated irrigation system is inconvenient since it must be constantly monitored. The trend in modern farming and gardening is to replace manually operated systems with sophisticated electromechanical or electronic control assemblies. Besides being costly and maintenance intensive, such assemblies require a power source. Battery powered sources are expensive and must be recharged, and conventional power sources require the stringing of transmission lines.
There has been an increasing interest in hydroponic farming and gardening in recent years. In hydroponic farming, plants grow in a non-nutritive root supporting mass such as sand, pebbles, or vermiculite and are periodically watered and fed with liquid fertilizer. Hydroponic farming has the same irrigation problems as does conventional farming, but with the added complication supplying the proper amount of liquid fertilizer to the plant roots. In consequence, the irrigation/fertilization control and distribution systems for hydroponic farming and gardening are typically much more complex than those for conventional farming, and thus more expensive and maintenance intensive. Again, an external source of power must be supplied to the hydroponic control assemblies known in the prior art.